Transmission slipping

[ElectroTech]

So I just finished building my XR10 and decided it would be fun to play around in the yard with my son. I let him drive my RTR SCX10 Honcho around while I was playing with the new XR. Long story short I start hearing a grinding sound and he's hitting the throttle and the SCX10 isn't moving, then it starts moving after moving it forward by hand.

I pulled the transmission and motor out and found there is a spot about 20 teeth where the metal pinion just ate the plastic spur gear.

I was going to upgrade and order a metal spur gear but cant seem to find a 32p 87t spur gear for the SCX10. I did find one for the EXO buggy will it work?

[Meatwad]

Stock gearing is 48p

A metal spur gear is greatly not needed, keep an eye on your gear mesh. Or step up to a 32p spur/pinion.

[k7zpj]

The Exo Spur won't work. It is meant to mount on the Exo's center diff.

The stock 48P works find unless you have a high power really fast motor.

If you want to go metal the Robinson Racing #1587 48P 87T works great and is only a couple bucks more than replacing with the stock plastic gear.

[wheelstoo]

32p Gears are larger than 48 gears.My 60t 32p spur is slightly larger than a 80t 48 spur.You just want to keep same ratio.There are charts on here I think that show ratios.

[Jus]

To keep the same final ratio just divide the spur gear teeth by the pinion.. So for 48P say 87 spur / 20 pinion that's a ratio of 4.35. For 32P gears a 56 spur / 13 pinion would be a ratio of 4.30.

[ElectroTech]

Ok I believe the pinion gear being loose caused my issues. The pinion was not tight and just slid easily up and down on the motor shaft. From looking at the destruction on the spur gear it looks as if the pinion started moving off one side and then once it only had about half of the length in teeth it started eating them. I think I'm just going to order a Robinson racing Super Spur 48p 87T. I tightened the pinion back down centered on the spur and it runs, just sounds like crap when the pinion spins around to the bad spot on the spur.

Here's the pic on the chewed up spur: